Procedures in hog production are improved and modified on an ongoing basis for the purposes of improving feed uptake efficiency and of improving the quality of life for the animals.
In recent years the production has been divided into separate sections with production barns dedicated to the separate sections rather than to the full life scale of the animal. One of these sections is the finisher section in which the animals are taken after weaning and after an initial growth stage and are then brought from the initial weight of the order of 60 lbs up to a market weight of the order of 250 lbs.
One technique which has been proposed recently is that of maintaining the hogs in a series of pens in the finisher barn in which animals of approximately the same weight are maintained in a common pen and then moved from that pen to the next pen.
In large scale production each pen could include 500 individual animals as a typical number with the range being of the order of 200 to 600. It will be appreciated that individual management of that number of hogs in a pen and management of transfer of that number of hog from one pen to the next is a difficult situation which is beyond the individual control of an operator observing the animals.
Sorting scales have been available in recent years which are used to weigh individual animals and, based upon the weight being above or below a certain value to guide the animal as it exits from the scale to one path or another. In this way the heavier animals can be selected and directed to a separate pen for example in a market situation to determine when the animals reach market weight. Such sorting scales have become widely used.
It has also been hypothesised that the animals can be managed, depending upon their weight to supply different types of feed materials so as to encourage rapid growth in animals which are growing less effectively or to provide a lower cost of feed for animals which are growing most effectively. If all the animals grew at the same rate, transfer of the animals through the pens would be relatively straight forward since all of the animals at a certain age would be moved. However unfortunately, for various reasons animals do not grow at the same rate and up till now their individuality has been difficult to manage.
One attempt to manage hogs within a hog barn is shown in U.S. Pat. No. 6,837,189 (Schick) issued Jan. 4, 2005. This provides an arrangement in which animals are sorted between light and heavy into two separate pens using a sorting scale. However this provides no system for controlling the density of animals within a particular pen.
Also published International application WO03/103380 (Thibault) assigned to Osborne Industries Inc and published Dec. 18, 2003 discloses a system of dividing animals into heavy weight pen and a lightweight pen using a sorting scale. However again it does not consider the issues of animal density within the pens.